The invention relates to an apparatus for the manufacture of bags from a web of thermoplastic material while applying the loop-formation principle, comprising a supply line for the web, a range of bearers for this web moving on in an endless circuit, which bearers also form an anvil each and a number of traveling welding devices which cooperate with the anvils on the bearers for cutting and heatsealing the web. Such an apparatus is described in, for instance, French Patent Specification No. 1.160.010.
Although this known apparatus has proved to operate very satisfactorily in practice, especially in the domain of household bags of thin-walled material, there is a great demand for a machine by which these bags can be manufactured at a high speed. Up to now, this high speed has always given rise to difficulties in connection with thin-walled plastic material, the handling of which is difficult.